Answer:
Si14- Si^4+
As33- As^3-
Mg12- Mg^2+
Rb37- Rb^+
F9- F^-
Ge32- Ge^4+
Sn50- Sn^2+, Sn^4+
Explanation:
The elements shown in the answer have their common ions written beside them.
Silicon mostly forms positive ions in oxyacids and complex ions. Arsenic mostly forms its anion. Magnesium forms only the +2cation just as rubidium only forms the +1 cation. The fluoride ion is F^- while tin may for a +2*or +4 cation. Germanium usually forms the +4 cation.
<span>0.925 grams if using hydrochloric acid in the reaction.
0.462 grams if using sulfuric acid in the reaction.
0.000 grams if using nitric acid in the reaction.
Assuming you're using HCl or a similar acid for this reaction, the equation for the reaction is:
Zn + 2 HCl ==> ZnCl2 + H2
So each mole of zinc used, produces 1 mole of hydrogen gas, or 2 moles of hydrogen atoms. So we need to look up the atomic weights of both zinc and hydrogen.
Atomic weight zinc = 65.38
Atomic weight hydrogen = 1.00794
Moles zinc = 30.0 g / 65.38 g/mol = 0.458855919 mol
Since we produce 2 moles of hydrogen atoms per mole of zinc, multiply by 2 and the atomic weight of hydrogen to get the mass of hydrogen produced. So
0.458855919 * 2 * 1.00794 = 0.92499847 grams.
Rounding to 3 significant figures gives 0.925 grams.
To show the assumption of the acid used, the balanced equation for sulfuric acid would be
Zn2 + H2SO4 ==> Zn(SO4)2 + H2
Which means that for every mole of zinc used, 1 mole of hydrogen gas is generated (half that produced via hydrochloric acid).
If nitric acid were used, the reaction is
4Zn + 10HNO3 ==> 4Zn(NO3)2 + N2O + 5H2O
Which means that NO hydrogen gas is generated.
The only justification for assuming hydrochloric acid is used is that it's a fairly common acid that's easy to obtain. But as shown above with 2 alternative acids, the amount of hydrogen gas generated is very dependent upon the exact chemical reaction occurring and asking "How many grams of hydrogen are produced if 30.0 g of zinc reacts?" is a rather silly question unless you specify EXACTLY what the reaction is.</span>
Answer:
The number of moles of potassium hydroxide, KOH required to make 4 moles of K₂SO₄ is 8 moles of KOH
Explanation:
2KOH + H₂SO₄ → K₂SO₄ + 2H₂O
From the above reaction, we have 2 moles of KOH combining with 1 mole of H₂SO₄ to produce 1 mole of K₂SO₄ and 2 moles of H₂O.
Therefore the number of moles of potassium hydroxide that will be needed to make 4 moles of K₂SO₄ is;
8KOH + 4H₂SO₄ → 4K₂SO₄ + 8H₂O
8 moles of KOH is required to make 4 moles of K₂SO₄.
Answer:
The correct order will be
a. Transfer the measured amount of NaCl to the volumetric flask.
e. Dissolve the NaCl in less than 250 mL of water and mix well.
b. Dilute the solution with water to the 250.0 mL mark.
Explanation:
Preparation of NaCl solution in 250.0 ml volumetric flask:
Add the weighed NaCl directly to volumetric flask and add small amount of water to it and mix it will until all NaCl gets dissolved( if not add small water amount of water more)
After dissolving NaCl add the water upto the mark.
The correct order will be
a. Transfer the measured amount of NaCl to the volumetric flask.
e. Dissolve the NaCl in less than 250 mL of water and mix well.
b. Dilute the solution with water to the 250.0 mL mark.
Answer:
The volumes are both, accurate and precise.
Explanation:
In the measurement of a set, precision refers to how much coincidence exists in the measurements of an specific value, as the measurements are close, we can say the volumes are precise.
Accuracy means the agreement that exists between the average of one
large series of measurements and the value of measurement
Media is 4,96 ml and I wanted to measure 5 ml. It is also close.
